1. Field of the Invention
The present invention relates in general to a base board for testing integrated circuits and, in particular, to such a board of the type which is rotated by a drive system to to provide automatic switchover of integrated circuit terminals in the circuit characteristic and electrostatic breakdown testing.
2. Description of the Prior Art
Various methods and devices for testing integrated circuits for fault or diode characteristics have been developed and well known. In some of then, charged electricity in a capacitor is applied to the integrated circuit to be tested across selected pairs of terminals to check the effect of such charge application on the circuit.
In the prior art, testing requires the terminals of an integrated circuit to be selected in pair in a proper sequence and connected, one pair at a time, to a charging capacitor through a switch system that performs the terminal selection.
One conventional example comprises a manual switch system for selecting terminal pairs. However, where a large number of integrated circuits have to be tested, tremendous operator attention and cumbersome labor are demanded, with attendant inefficiency of operation.
In another example of the prior art, a relay circuit system is provided which comprises a number of lead wires. The wires are connected at their opposite end to the terminals of an integrated circuit to be tested. Means are provided to automatically connect the lead wires in pair to a capacitor which charges the terminals linked to the wires now connected. Because of the design requirements of such relay circuit systems, the lead wires are generally made long, with a resultant excessive increase in the distance between the charging capacitor and integrated circuit terminals to be tested. As a result, various problems arise.
Generally, the stray capacitance of the electric circuit depends on the length of the lead wires connected to the relay circuit due to floating capacitance present in the circuit between the lead wires and earthing. Floating capacitance is likely to invite inaccuracy in the measurement of electricity charged in a capacitor.
Thus, great demand has been placed on the development of a more efficient device for testing integrated circuits in which the terminals of an integrated circuit to be tested are selected in an automatic and easy manner for static charge application from a capacitor in the operating characteristic or electrostatic breakdown testing.